Epoxy resins are used for various applications due to excellent heat resistance. In recent years, improvement in thermal conductivity of epoxy resins has been studied in view of increasing use temperature of power devices in which epoxy resins are used.
An epoxy resin that has a mesogenic structure in its molecule and exhibits liquid crystallinity in a cured state (hereinafter, also referred to as a liquid-crystalline epoxy resin) is known to have excellent thermal conductivity. However, liquid-crystalline epoxy resins generally have higher viscosity and lower fluidity as compared with other epoxy resins, and have unfavorable moldability (or requires heating to melt) since the resins are crystallized during storage. For reasons such as these, there is room for improvement in the handleability of liquid-crystalline epoxy resins.
As a liquid-crystalline epoxy resin having improved fluidity, a liquid-crystalline epoxy resin including a multimer, which is formed by reaction of an epoxy monomer having a mesogenic structure and a divalent phenol compound, has been proposed (see Patent Document 1).